The present invention relates to the light duty gasoline engine, and particularly to the ignition control device for use with light duty gasoline engine and method of suppressing reverse rotation of the engine during startup process of the light duty gasoline engine.
Gasoline Engine always needs an ignition signal from an igniter on an appropriate time point, and power is provided, by combustion of Fuel-Air Mixture in the cylinder in control, to keep gasoline engine running continuously. For light duty gasoline engine, Electronic Fuel Injection (EFI) is rarely used, whereas Ignition Advance Angle of the engine is controlled separately to implement the corresponding control functions. The moment when Fuel-Air Mixture is compressed to its possible minimum volume by Piston in the cylinder is called the Top Dead Center (TDC). In principle, it is needed to get a full burn for Fuel-Air Mixture when Top Dead Center occurs so as to generate the energy to push the piston furthest to bring about a maximum power for the Gasoline Engine. But it takes time for igniter to generate an ignition signal and for Fuel-Air Mixture to be ignited and get a full burn. If the igniter always generate the ignition signal at Top Dead Center (TDC), then with a growing rotation speed of the Gasoline Engine, the time interval between the moment that Fuel-Air Mixture gets a full burn in the cylinder and the moment that Piston arrives at Top Dead Center (TDC) becomes bigger and bigger, and consequently, work efficiency of the Gasoline Engine becomes lower and lower.
Besides, light duty gasoline engine is generally designed in a unidirectional rotation mode, namely, light duty gasoline engine can only rotate in one way. And rotation axis and startup wheel of the gasoline engine are closely jointed in the unidirectional mode. That is, if gasoline engine rotates positively, rotation axis can run normally regardless of the startup wheel; if gasoline engine rotates reversely, rotation axis will run in a reverse way forcing startup wheel to follow it. The startup wheel is wound by a certain length of startup rope so that some positive rotation energy is forced onto the rotation axis and the fly wheel of the gasoline with the startup rope being pulled and with cooperation of the igniting function of igniter, engine can be started normally. During the start-up process of the engine, the speed of rotation axis varies, which will leads that ignition angle calculated by ignition system (particularly for the digital ignition system) to deviate the actually required angle, or even lead to a transient reverse rotation of the rotation axis of the gasoline engine. A reverse rotation of startup wheel causes that the startup rope may more and more tighter with its reverse rotation, and the startup rope may be broken to cause a damage to the startup system once tension goes too much for the startup rope.